The project will build on the World Health Organization Determinants of Outcome Study. 1379 patients in 13 participating centers were assessed at the onset of psychosis (in 1978-1980) and followed up for two years. Comparable and reliable methods were used in each participating center for case identification and follow up, and in most centers the cases were closely representative of all new onsets of nonaffective psychosis within a specified time period. Thus, the generalizability of findings is secure, and comparisons across (as well as within) nations are possible. First, further analyses of the two year follow up data are proposed. These focus primarily on cross national variation in etiology and course of schizophrenia, and on detection of subgroups of patients with a distinct etiology and course that are consistently apparent across nations. The analysis of whether gender differences in schizophrenia vary between developing and industrialized countries is selected for detailed presentation in the grant application. Second, ground work for an eventual cross national follow up and family/genetic study based on the same sample is proposed. The groundwork funded by this grant application would involve a check on whether patients and first degree relatives can be located, and a modification of one of the Determinants of Outcome Study short term follow up instruments for use in a long term follow up. Third, a long term follow up study is proposed. The patients are now in their second decade since onset of psychosis. The FIRST award will fund one center, in a developing country, to carry out the follow up study. This will be the first long term and prospective follow up study of an incident sample of patients with schizophrenia in a developing country. It is expected that other Determinants of Outcome field research centers will acquire the necessary resources from other sources and choose to participate in a collaborative long term follow up study.